"Good" fats like monounsaturated fats and "bad" fats like trans and saturated fats aren't just factors in heart health -- a new study shows they can affect brain health and memory, too.
Researchers from Brigham and Women's Hospital found that women who consumed the most "bad" fats in their study were also the ones who had the worse memory and brain functioning over the four-year study period, compared with women who consumed the fewest "bad" fats.
Meanwhile, women who consumed the most "good" fats scored better on cognitive tests during the study.
Saturated fats are commonly found in animal products, like butter and red meat, while monounsaturated fats are found in olive oil, among other foods.
"When looking at changes in cognitive function, what we found is that the total amount of fat intake did not really matter, but the type of fat did," study researcher Dr. Olivia Okereke, M.D., of the Brigham and Women's Hospital Department of Psychiatry, said in a statement.
The study, published in the journal Annals of Neurology, included data from 6,000 women who were part of the Women's Health Study. These women, who were all age 45 and older, participated in a cognitive functioning test every two years over a four-year period, and also completed food questionnaires at the start of the study.
"Our findings have significant public health implications," Okereke said in the statement. "Substituting in the good fat in place of the bad fat is a fairly simple dietary modification that could help prevent decline in memory."
Last year, a study in the journal Neurology showed that people who have high trans fat levels in their blood also had performed worse on cognitive tests, HuffPost Food reported. They also had decreased total brain volume.
"It's clear that trans fats are bad -- both for your heart and now, we see, for your brain," the researcher of that study, Dr. Gene Bowman of Oregon Health & Science University, told HuffPost Food. "So I would recommend that people stay away from all trans fats. If you aren't sure whether something has them, just look at the ingredients; if there's vegetable shortening, partially hydrogenated anything ... just put it down. That's the big message here."
For more on how fat affects the body -- and how much of it we should be eating -- check out this Health.com piece on good and bad fats.